I think it is to protect the engine from too heavy of an oil on cold starts. It certainly is not a new idea. My 77 LUV, SOHC, must hold about a quart, and I think they were using the same engine for years. I too have thought about drilling a hole. With 5W-30 and an ST filter, it should get oil to the top fairly quickly. The oil pan also has a dead spot that must hold about a quart. Drain 6 and leave 2? I jump up and down on the bumper, trying to slosh more oil out.